Aim: How does the structure of the cell membrane allow for its

function?DO NOW:

1. Why do cells have a membrane?2. Why does an apple have skin?

3. Think about a castle. What structure would be similar to a cell membrane?

Cell Membrane• In both plant & animal cells• Also called plasma membrane• Barrier separates the outside from the inside of a cell• Selectively permeable: regulates transport of

materials that come into or out of cell• Made of lipids (fats), cholesterol & protein• 2 layers: “phospholipid bi-layer” (sandwich)• flexible• Contains receptors for cell communication • (ex. Hormones binding to cells)

Cell Membrane in Animal & Plant Cells

Cell Membrane Receptors

Transport Across Cell Membrane

Cell Membrane & Cell Homeostasis

• Since it is selectively permeable, cells can maintain stability or balance

• harmful substances may be kept out of cell• Lets wastes leave cells

“Membrane, What can move across you, to enter or leave the cell?”

• Small sized molecules, such as digested food (nutrients)

• Oxygen• Carbon dioxide• Water

“Membrane, What can’t move across you to enter or leave the cell?”

• Large sized molecules, such as starch (complex carbohydrate)

• proteins• Fats• Digestion or breakdown into simple subunits

or building blocks must take place first!!!

Video

• https://app.discoveryeducation.com/learn/videos/ADEE143F-3029-4292-83AC-A84B8ED4E906?hasLocalHost=false

• https://app.discoveryeducation.com/learn/videos/66FE3E26-DC36-4174-8C93-969405E95E43?hasLocalHost=false

• https://app.discoveryeducation.com/learn/videos/D331500E-2C3D-4327-918F-F07DE222F65E?hasLocalHost=false

Homework

• Read textbook pages 187-190 and answer questions 1, 2 & 3 on page 190. Write out questions and answers.